Understood, maybe I learn Polish, right?
Maybe not. That isn't going to happen. You have demonstrated no serious motivation to do so. And if there's one thing your going to need while learning Polish, it's motivation. Lots and lots of motivation.
There's something bothering me here, or a few things.
I'm not seeing any evidence that you know anything at all about Poland other than its position on a map.
I'm not seeing any evidence that you have a concrete plan of what you intend to do while in Poland.
I'm not seeing any evidence that you have researched the universities in Poland to decide which would offer the best circumstances to carry out your plan, if you have one.
I'm not seeing any evidence that you have reached out to any Polish academics working on your specific area of interest.
You seem to be more concerned about choosing a city, not the best university department to further your education.
In short, I'm not seeing any evidence that you are an attractive candidate for an Erasmus scholarship.
Why do you want to come to Poland, and what do you plan on doing there? It would help if you shared this information with us, we can provide you with useful information.